DISTRIBUTION, ABUNDANCE AND ENERGY RELATIONSHIPS OF WADERS (AVES: CHARADRII) AT LANGEBAAN LAGOON

Summary

The distribution and numbers of waders on the low-tide sandflats and at high-tide roosts at Langebaan Lagoon during the austral summer of 1975–6 are described. The sandflats in Rietbaai, and at the lower and upper sections of the lagoon supported the highest densities of waders. Several species were restricted in their distribution. The majority of the high-tide roosts, incorporating some 30 000 waders, were situated on Arthrocnemum saltmarsh, especially between Bottelary and Geelbek. Approximately 1 000 waders (3 % of the lagoon's population) roosted on the beaches along the Atlantic coastline at high tide. Many thousands roosted on the beach north of Langebaan village at night. The wader community consumed an estimated quantity of food equivalent to 20,8 kcal/m² per year. Between 2,1 and 6,2 kcal/m² per year are returned as faeces to the lagoon system. Feather material deposited in the lagoon was equivalent to 0,06 kcal/m² per year.